From 94ed465404cc387aae1bdc40f4d216a43842f254 Mon Sep 17 00:00:00 2001
From: Zach Klippenstein <git@zachklipp.com>
Date: Mon, 23 Jun 2025 17:30:15 -0700
Subject: [PATCH 1/2] Refactor WorkflowNode into AbstractWorkflowNode <-
 StatefulWorkflowNode.

This is to prepare for go/compose-based-workflows.
---
 .../squareup/workflow1/WorkflowInterceptor.kt |  13 ++
 .../internal/AbstractWorkflowNode.kt          | 130 ++++++++++++++++
 ...orkflowNode.kt => StatefulWorkflowNode.kt} | 139 ++++++++----------
 .../workflow1/internal/SubtreeManager.kt      |  21 ++-
 .../workflow1/internal/WorkflowChildNode.kt   |  13 +-
 .../workflow1/internal/WorkflowRunner.kt      |  16 +-
 ...odeTest.kt => StatefulWorkflowNodeTest.kt} | 119 +++++++--------
 7 files changed, 288 insertions(+), 163 deletions(-)
 create mode 100644 workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/AbstractWorkflowNode.kt
 rename workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/{WorkflowNode.kt => StatefulWorkflowNode.kt} (75%)
 rename workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/{WorkflowNodeTest.kt => StatefulWorkflowNodeTest.kt} (94%)

diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/WorkflowInterceptor.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/WorkflowInterceptor.kt
index 324ed39ae4..9035998718 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/WorkflowInterceptor.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/WorkflowInterceptor.kt
@@ -1,6 +1,7 @@
 package com.squareup.workflow1
 
 import com.squareup.workflow1.WorkflowInterceptor.RenderContextInterceptor
+import com.squareup.workflow1.WorkflowInterceptor.RuntimeUpdate
 import com.squareup.workflow1.WorkflowInterceptor.WorkflowSession
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
@@ -194,6 +195,8 @@ public interface WorkflowInterceptor {
   /**
    * Information about the session of a workflow in the runtime that a [WorkflowInterceptor] method
    * is intercepting.
+   *
+   * Implementations should override [toString] to call [WorkflowSession.workflowSessionToString].
    */
   public interface WorkflowSession {
     /** The [WorkflowIdentifier] that represents the type of this workflow. */
@@ -419,6 +422,16 @@ internal fun <P, S, O, R> WorkflowInterceptor.intercept(
   }
 }
 
+internal fun WorkflowSession.workflowSessionToString(): String {
+  val parentDescription = parent?.let { "WorkflowInstance(…)" }
+  return "WorkflowInstance(" +
+    "identifier=$identifier, " +
+    "renderKey=$renderKey, " +
+    "instanceId=$sessionId, " +
+    "parent=$parentDescription" +
+    ")"
+}
+
 private class InterceptedRenderContext<P, S, O>(
   private val baseRenderContext: BaseRenderContext<P, S, O>,
   private val interceptor: RenderContextInterceptor<P, S, O>
diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/AbstractWorkflowNode.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/AbstractWorkflowNode.kt
new file mode 100644
index 0000000000..18df86a7c0
--- /dev/null
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/AbstractWorkflowNode.kt
@@ -0,0 +1,130 @@
+package com.squareup.workflow1.internal
+
+import com.squareup.workflow1.ActionApplied
+import com.squareup.workflow1.ActionProcessingResult
+import com.squareup.workflow1.ActionsExhausted
+import com.squareup.workflow1.NoopWorkflowInterceptor
+import com.squareup.workflow1.RuntimeConfig
+import com.squareup.workflow1.RuntimeConfigOptions
+import com.squareup.workflow1.TreeSnapshot
+import com.squareup.workflow1.Workflow
+import com.squareup.workflow1.WorkflowInterceptor
+import com.squareup.workflow1.WorkflowInterceptor.WorkflowSession
+import com.squareup.workflow1.WorkflowTracer
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.CoroutineName
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.selects.SelectBuilder
+import kotlin.coroutines.CoroutineContext
+
+internal fun <PropsT, OutputT, RenderingT> createWorkflowNode(
+  id: WorkflowNodeId,
+  workflow: Workflow<PropsT, OutputT, RenderingT>,
+  initialProps: PropsT,
+  snapshot: TreeSnapshot?,
+  baseContext: CoroutineContext,
+  // Providing default value so we don't need to specify in test.
+  runtimeConfig: RuntimeConfig = RuntimeConfigOptions.DEFAULT_CONFIG,
+  workflowTracer: WorkflowTracer? = null,
+  emitAppliedActionToParent: (ActionApplied<OutputT>) -> ActionProcessingResult = { it },
+  parent: WorkflowSession? = null,
+  interceptor: WorkflowInterceptor = NoopWorkflowInterceptor,
+  idCounter: IdCounter? = null
+): AbstractWorkflowNode<PropsT, OutputT, RenderingT> = StatefulWorkflowNode(
+  id = id,
+  workflow = workflow.asStatefulWorkflow(),
+  initialProps = initialProps,
+  snapshot = snapshot,
+  baseContext = baseContext,
+  runtimeConfig = runtimeConfig,
+  workflowTracer = workflowTracer,
+  emitAppliedActionToParent = emitAppliedActionToParent,
+  parent = parent,
+  interceptor = interceptor,
+  idCounter = idCounter,
+)
+
+internal abstract class AbstractWorkflowNode<PropsT, OutputT, RenderingT>(
+  val id: WorkflowNodeId,
+  protected val interceptor: WorkflowInterceptor,
+  protected val emitAppliedActionToParent: (ActionApplied<OutputT>) -> ActionProcessingResult,
+  baseContext: CoroutineContext,
+) {
+
+  /**
+   * Scope that has a job that will live as long as this node and be cancelled when [cancel] is
+   * called.
+   * Also adds a debug name to this coroutine based on its ID.
+   */
+  val scope: CoroutineScope = CoroutineScope(
+    baseContext +
+      Job(parent = baseContext[Job]) +
+      CoroutineName(id.toString())
+  )
+
+  /**
+   * The [WorkflowSession] that represents this node to [WorkflowInterceptor]s.
+   */
+  abstract val session: WorkflowSession
+
+  /**
+   * Walk the tree of workflows, rendering each one and using
+   * [RenderContext][com.squareup.workflow1.BaseRenderContext] to give its children a chance to
+   * render themselves and aggregate those child renderings.
+   *
+   * @param workflow The "template" workflow instance used in the current render pass. This isn't
+   * necessarily the same _instance_ every call, but will be the same _type_.
+   */
+  abstract fun render(
+    workflow: Workflow<PropsT, OutputT, RenderingT>,
+    input: PropsT
+  ): RenderingT
+
+  /**
+   * Walk the tree of state machines again, this time gathering snapshots and aggregating them
+   * automatically.
+   */
+  abstract fun snapshot(): TreeSnapshot
+
+  /**
+   * Register select clauses for the next [result][ActionProcessingResult] from the state machine.
+   *
+   * Walk the tree of state machines, asking each one to wait for its next event. If something
+   * happens that results in an output, that output is returned. Null means something happened that
+   * requires a re-render, e.g. my state changed or a child state changed.
+   *
+   * It is an error to call this method after calling [cancel].
+   *
+   * Contrast this to [applyNextAvailableTreeAction], which is used to check for an action
+   * that is already available without waiting, and then _immediately_ apply it.
+   */
+  abstract fun registerTreeActionSelectors(selector: SelectBuilder<ActionProcessingResult>)
+
+  /**
+   * Will try to apply any immediately available actions in this action queue or any of our
+   * children's.
+   *
+   * Contrast this to [registerTreeActionSelectors] which will add select clauses that will await
+   * the next action.
+   *
+   * @param skipDirtyNodes Whether or not this should skip over any workflow nodes that are already
+   * 'dirty' - that is, they had their own state changed as the result of a previous action before
+   * the next render pass.
+   *
+   * @return [ActionProcessingResult] of the action processed, or [ActionsExhausted] if there were
+   * none immediately available.
+   */
+  abstract fun applyNextAvailableTreeAction(skipDirtyNodes: Boolean = false): ActionProcessingResult
+
+  /**
+   * Cancels this state machine host, and any coroutines started as children of it.
+   *
+   * This must be called when the caller will no longer call [registerTreeActionSelectors]. It is an
+   * error to call [registerTreeActionSelectors] after calling this method.
+   */
+  open fun cancel(cause: CancellationException? = null) {
+    scope.cancel(cause)
+  }
+}
diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowNode.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/StatefulWorkflowNode.kt
similarity index 75%
rename from workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowNode.kt
rename to workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/StatefulWorkflowNode.kt
index 22b2d5d31c..b8f195b54b 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowNode.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/StatefulWorkflowNode.kt
@@ -24,12 +24,12 @@ import com.squareup.workflow1.intercept
 import com.squareup.workflow1.internal.RealRenderContext.RememberStore
 import com.squareup.workflow1.internal.RealRenderContext.SideEffectRunner
 import com.squareup.workflow1.trace
+import com.squareup.workflow1.workflowSessionToString
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineName
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.CoroutineStart.LAZY
 import kotlinx.coroutines.Job
-import kotlinx.coroutines.cancel
 import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.channels.Channel.Factory.UNLIMITED
 import kotlinx.coroutines.launch
@@ -49,8 +49,8 @@ import kotlin.reflect.KType
  * structured concurrency).
  */
 @OptIn(WorkflowExperimentalApi::class, WorkflowExperimentalRuntime::class)
-internal class WorkflowNode<PropsT, StateT, OutputT, RenderingT>(
-  val id: WorkflowNodeId,
+internal class StatefulWorkflowNode<PropsT, StateT, OutputT, RenderingT>(
+  id: WorkflowNodeId,
   workflow: StatefulWorkflow<PropsT, StateT, OutputT, RenderingT>,
   initialProps: PropsT,
   snapshot: TreeSnapshot?,
@@ -58,29 +58,33 @@ internal class WorkflowNode<PropsT, StateT, OutputT, RenderingT>(
   // Providing default value so we don't need to specify in test.
   override val runtimeConfig: RuntimeConfig = RuntimeConfigOptions.DEFAULT_CONFIG,
   override val workflowTracer: WorkflowTracer? = null,
-  private val emitAppliedActionToParent: (ActionApplied<OutputT>) -> ActionProcessingResult =
-    { it },
+  emitAppliedActionToParent: (ActionApplied<OutputT>) -> ActionProcessingResult = { it },
   override val parent: WorkflowSession? = null,
-  private val interceptor: WorkflowInterceptor = NoopWorkflowInterceptor,
+  interceptor: WorkflowInterceptor = NoopWorkflowInterceptor,
   idCounter: IdCounter? = null
-) : CoroutineScope, SideEffectRunner, RememberStore, WorkflowSession {
-
-  /**
-   * Context that has a job that will live as long as this node.
-   * Also adds a debug name to this coroutine based on its ID.
-   */
-  override val coroutineContext = baseContext + Job(baseContext[Job]) + CoroutineName(id.toString())
-
-  // WorkflowInstance properties
+) : AbstractWorkflowNode<PropsT, OutputT, RenderingT>(
+  id = id,
+  baseContext = baseContext,
+  interceptor = interceptor,
+  emitAppliedActionToParent = emitAppliedActionToParent,
+),
+  SideEffectRunner,
+  RememberStore,
+  WorkflowSession {
+
+  // WorkflowSession properties
   override val identifier: WorkflowIdentifier get() = id.identifier
   override val renderKey: String get() = id.name
   override val sessionId: Long = idCounter.createId()
   private var cachedWorkflowInstance: StatefulWorkflow<PropsT, StateT, OutputT, RenderingT>
   private var interceptedWorkflowInstance: StatefulWorkflow<PropsT, StateT, OutputT, RenderingT>
 
+  override val session: WorkflowSession
+    get() = this
+
   private val subtreeManager = SubtreeManager(
     snapshotCache = snapshot?.childTreeSnapshots,
-    contextForChildren = coroutineContext,
+    contextForChildren = scope.coroutineContext,
     emitActionToParent = ::applyAction,
     runtimeConfig = runtimeConfig,
     workflowTracer = workflowTracer,
@@ -117,22 +121,21 @@ internal class WorkflowNode<PropsT, StateT, OutputT, RenderingT>(
   private val context = RenderContext(baseRenderContext, workflow)
 
   init {
-    interceptor.onSessionStarted(this, this)
+    interceptor.onSessionStarted(workflowScope = scope, session = this)
 
     cachedWorkflowInstance = workflow
-    interceptedWorkflowInstance = interceptor.intercept(cachedWorkflowInstance, this)
-    state = interceptedWorkflowInstance.initialState(initialProps, snapshot?.workflowSnapshot, this)
+    interceptedWorkflowInstance = interceptor.intercept(
+      workflow = cachedWorkflowInstance,
+      workflowSession = this
+    )
+    state = interceptedWorkflowInstance.initialState(
+      props = initialProps,
+      snapshot = snapshot?.workflowSnapshot,
+      workflowScope = scope
+    )
   }
 
-  override fun toString(): String {
-    val parentDescription = parent?.let { "WorkflowInstance(…)" }
-    return "WorkflowInstance(" +
-      "identifier=$identifier, " +
-      "renderKey=$renderKey, " +
-      "instanceId=$sessionId, " +
-      "parent=$parentDescription" +
-      ")"
-  }
+  override fun toString(): String = workflowSessionToString()
 
   /**
    * Walk the tree of workflows, rendering each one and using
@@ -140,29 +143,32 @@ internal class WorkflowNode<PropsT, StateT, OutputT, RenderingT>(
    * render themselves and aggregate those child renderings.
    */
   @Suppress("UNCHECKED_CAST")
-  fun render(
-    workflow: StatefulWorkflow<PropsT, *, OutputT, RenderingT>,
+  override fun render(
+    workflow: Workflow<PropsT, OutputT, RenderingT>,
     input: PropsT
-  ): RenderingT =
-    renderWithStateType(workflow as StatefulWorkflow<PropsT, StateT, OutputT, RenderingT>, input)
+  ): RenderingT = renderWithStateType(
+    workflow = workflow.asStatefulWorkflow() as
+      StatefulWorkflow<PropsT, StateT, OutputT, RenderingT>,
+    props = input
+  )
 
   /**
    * Walk the tree of state machines again, this time gathering snapshots and aggregating them
    * automatically.
    */
-  fun snapshot(workflow: StatefulWorkflow<*, *, *, *>): TreeSnapshot {
-    @Suppress("UNCHECKED_CAST")
-    val typedWorkflow = workflow as StatefulWorkflow<PropsT, StateT, OutputT, RenderingT>
-    maybeUpdateCachedWorkflowInstance(typedWorkflow)
-    return interceptor.onSnapshotStateWithChildren({
-      val childSnapshots = subtreeManager.createChildSnapshots()
-      val rootSnapshot = interceptedWorkflowInstance.snapshotState(state)
-      TreeSnapshot(
-        workflowSnapshot = rootSnapshot,
-        // Create the snapshots eagerly since subtreeManager is mutable.
-        childTreeSnapshots = { childSnapshots }
-      )
-    }, this)
+  override fun snapshot(): TreeSnapshot {
+    return interceptor.onSnapshotStateWithChildren(
+      proceed = {
+        val childSnapshots = subtreeManager.createChildSnapshots()
+        val rootSnapshot = interceptedWorkflowInstance.snapshotState(state)
+        TreeSnapshot(
+          workflowSnapshot = rootSnapshot,
+          // Create the snapshots eagerly since subtreeManager is mutable.
+          childTreeSnapshots = { childSnapshots }
+        )
+      },
+      session = this
+    )
   }
 
   override fun runningSideEffect(
@@ -206,20 +212,7 @@ internal class WorkflowNode<PropsT, StateT, OutputT, RenderingT>(
     return result.lastCalculated as ResultT
   }
 
-  /**
-   * Register select clauses for the next [result][ActionProcessingResult] from the state machine.
-   *
-   * Walk the tree of state machines, asking each one to wait for its next event. If something happen
-   * that results in an output, that output is returned. Null means something happened that requires
-   * a re-render, e.g. my state changed or a child state changed.
-   *
-   * It is an error to call this method after calling [cancel].
-   *
-   * Contrast this to [applyNextAvailableTreeAction], which is used to check for an action
-   * that is already available without waiting, and then _immediately_ apply it.
-   * The select clauses added here also call [applyAction] when one of them is selected.
-   */
-  fun registerTreeActionSelectors(selector: SelectBuilder<ActionProcessingResult>) {
+  override fun registerTreeActionSelectors(selector: SelectBuilder<ActionProcessingResult>) {
     // Listen for any child workflow updates.
     subtreeManager.registerChildActionSelectors(selector)
 
@@ -231,22 +224,7 @@ internal class WorkflowNode<PropsT, StateT, OutputT, RenderingT>(
     }
   }
 
-  /**
-   * Will try to apply any immediately available actions in this action queue or any of our
-   * children's.
-   *
-   * Contrast this to [registerTreeActionSelectors] which will add select clauses that will await
-   * the next action. That will also end up with [applyAction] being called when the clauses is
-   * selected.
-   *
-   * @param skipDirtyNodes Whether or not this should skip over any workflow nodes that are already
-   * 'dirty' - that is, they had their own state changed as the result of a previous action before
-   * the next render pass.
-   *
-   * @return [ActionProcessingResult] of the action processed, or [ActionsExhausted] if there were
-   * none immediately available.
-   */
-  fun applyNextAvailableTreeAction(skipDirtyNodes: Boolean = false): ActionProcessingResult {
+  override fun applyNextAvailableTreeAction(skipDirtyNodes: Boolean): ActionProcessingResult {
     if (skipDirtyNodes && selfStateDirty) return ActionsExhausted
 
     val result = subtreeManager.applyNextAvailableChildAction(skipDirtyNodes)
@@ -262,11 +240,11 @@ internal class WorkflowNode<PropsT, StateT, OutputT, RenderingT>(
   /**
    * Cancels this state machine host, and any coroutines started as children of it.
    *
-   * This must be called when the caller will no longer call [registerTreeActionSelectors]. It is an error to call [registerTreeActionSelectors]
-   * after calling this method.
+   * This must be called when the caller will no longer call [registerTreeActionSelectors]. It is an
+   * error to call [registerTreeActionSelectors] after calling this method.
    */
-  fun cancel(cause: CancellationException? = null) {
-    coroutineContext.cancel(cause)
+  override fun cancel(cause: CancellationException?) {
+    super.cancel(cause)
     lastRendering = NullableInitBox()
   }
 
@@ -348,7 +326,6 @@ internal class WorkflowNode<PropsT, StateT, OutputT, RenderingT>(
    * Applies [action] to this workflow's [state] and then passes the resulting [ActionApplied]
    * via [emitAppliedActionToParent] to the parent, with additional information as to whether or
    * not this action has changed the current node's state.
-   *
    */
   private fun applyAction(
     action: WorkflowAction<PropsT, StateT, OutputT>,
@@ -389,7 +366,7 @@ internal class WorkflowNode<PropsT, StateT, OutputT, RenderingT>(
     sideEffect: suspend CoroutineScope.() -> Unit
   ): SideEffectNode {
     return workflowTracer.trace("CreateSideEffectNode") {
-      val scope = this + CoroutineName("sideEffect[$key] for $id")
+      val scope = scope + CoroutineName("sideEffect[$key] for $id")
       val job = scope.launch(start = LAZY, block = sideEffect)
       SideEffectNode(key, job)
     }
diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/SubtreeManager.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/SubtreeManager.kt
index 7cf7ab163b..62c0010ea9 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/SubtreeManager.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/SubtreeManager.kt
@@ -20,14 +20,14 @@ import kotlin.coroutines.CoroutineContext
  * Responsible for tracking child workflows, starting them and tearing them down when necessary.
  * Also manages restoring children from snapshots.
  *
- * Child workflows are stored in [WorkflowChildNode]s, which associate the child's [WorkflowNode]
+ * Child workflows are stored in [WorkflowChildNode]s, which associate the child's [AbstractWorkflowNode]
  * with its output handler.
  *
  * ## Rendering
  *
- * This class implements [RealRenderContext.Renderer], and [WorkflowNode] will pass its instance
- * of this class to the [RealRenderContext] on each render pass to render children. That means that
- * when a workflow renders a child, this class does the actual work.
+ * This class implements [RealRenderContext.Renderer], and [StatefulWorkflowNode] will pass its
+ * instance of this class to the [RealRenderContext] on each render pass to render children. That
+ * means that when a workflow renders a child, this class does the actual work.
  *
  * This class keeps two lists:
  *  1. Active list: All the children from the last render pass that have not yet been rendered in
@@ -55,7 +55,7 @@ import kotlin.coroutines.CoroutineContext
  *      active:  [bar]
  *      staging: [foo, baz]
  *      ```
- *   4. When the workflow's render method returns, the [WorkflowNode] calls
+ *   4. When the workflow's render method returns, the [StatefulWorkflowNode] calls
  *      [commitRenderedChildren], which:
  *        1. Tears down all the children remaining in the active list
  *           ```
@@ -143,11 +143,11 @@ internal class SubtreeManager<PropsT, StateT, OutputT>(
         )
       }
     stagedChild.setHandler(handler)
-    return stagedChild.render(child.asStatefulWorkflow(), props)
+    return stagedChild.render(child, props)
   }
 
   /**
-   * Uses [selector] to invoke [WorkflowNode.registerTreeActionSelectors] for every running child
+   * Uses [selector] to invoke [AbstractWorkflowNode.registerTreeActionSelectors] for every running child
    * workflow this instance is managing.
    */
   fun registerChildActionSelectors(selector: SelectBuilder<ActionProcessingResult>) {
@@ -179,8 +179,7 @@ internal class SubtreeManager<PropsT, StateT, OutputT>(
   fun createChildSnapshots(): Map<WorkflowNodeId, TreeSnapshot> {
     val snapshots = mutableMapOf<WorkflowNodeId, TreeSnapshot>()
     children.forEachActive { child ->
-      val childWorkflow = child.workflow.asStatefulWorkflow()
-      snapshots[child.id] = child.workflowNode.snapshot(childWorkflow)
+      snapshots[child.id] = child.workflowNode.snapshot()
     }
     return snapshots
   }
@@ -205,9 +204,9 @@ internal class SubtreeManager<PropsT, StateT, OutputT>(
 
     val childTreeSnapshots = snapshotCache?.get(id)
 
-    val workflowNode = WorkflowNode(
+    val workflowNode = createWorkflowNode(
       id = id,
-      workflow = child.asStatefulWorkflow(),
+      workflow = child,
       initialProps = initialProps,
       snapshot = childTreeSnapshots,
       baseContext = contextForChildren,
diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowChildNode.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowChildNode.kt
index ea2d468766..329174c5bd 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowChildNode.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowChildNode.kt
@@ -1,6 +1,5 @@
 package com.squareup.workflow1.internal
 
-import com.squareup.workflow1.StatefulWorkflow
 import com.squareup.workflow1.Workflow
 import com.squareup.workflow1.WorkflowAction
 import com.squareup.workflow1.WorkflowTracer
@@ -10,7 +9,7 @@ import com.squareup.workflow1.trace
 /**
  * Representation of a child workflow that has been rendered by another workflow.
  *
- * Associates the child's [WorkflowNode] (which includes the key passed to `renderChild`) with the
+ * Associates the child's [AbstractWorkflowNode] (which includes the key passed to `renderChild`) with the
  * output handler function that was passed to `renderChild`.
  */
 internal class WorkflowChildNode<
@@ -22,11 +21,11 @@ internal class WorkflowChildNode<
   >(
   val workflow: Workflow<*, ChildOutputT, *>,
   private var handler: (ChildOutputT) -> WorkflowAction<ParentPropsT, ParentStateT, ParentOutputT>,
-  val workflowNode: WorkflowNode<ChildPropsT, *, ChildOutputT, *>
+  val workflowNode: AbstractWorkflowNode<ChildPropsT, ChildOutputT, *>
 ) : InlineListNode<WorkflowChildNode<*, *, *, *, *>> {
   override var nextListNode: WorkflowChildNode<*, *, *, *, *>? = null
 
-  /** The [WorkflowNode]'s [WorkflowNodeId]. */
+  /** The [AbstractWorkflowNode]'s [WorkflowNodeId]. */
   val id get() = workflowNode.id
 
   /**
@@ -48,15 +47,15 @@ internal class WorkflowChildNode<
   }
 
   /**
-   * Wrapper around [WorkflowNode.render] that allows calling it with erased types.
+   * Wrapper around [AbstractWorkflowNode.render] that allows calling it with erased types.
    */
   fun <R> render(
-    workflow: StatefulWorkflow<*, *, *, *>,
+    workflow: Workflow<*, *, *>,
     props: Any?
   ): R {
     @Suppress("UNCHECKED_CAST")
     return workflowNode.render(
-      workflow as StatefulWorkflow<ChildPropsT, *, ChildOutputT, Nothing>,
+      workflow as Workflow<ChildPropsT, ChildOutputT, Nothing>,
       props as ChildPropsT
     ) as R
   }
diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowRunner.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowRunner.kt
index 25e9b15f49..7761aacb31 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowRunner.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowRunner.kt
@@ -47,7 +47,7 @@ internal class WorkflowRunner<PropsT, OutputT, RenderingT>(
   private val propsChannel = props.dropWhile { it == currentProps }
     .produceIn(scope)
 
-  private val rootNode = WorkflowNode(
+  private val rootNode = createWorkflowNode(
     id = workflow.id(),
     workflow = workflow,
     initialProps = currentProps,
@@ -66,11 +66,15 @@ internal class WorkflowRunner<PropsT, OutputT, RenderingT>(
    * between every subsequent call to [awaitAndApplyAction].
    */
   fun nextRendering(): RenderingAndSnapshot<RenderingT> {
-    return interceptor.onRenderAndSnapshot(currentProps, { props ->
-      val rendering = rootNode.render(workflow, props)
-      val snapshot = rootNode.snapshot(workflow)
-      RenderingAndSnapshot(rendering, snapshot)
-    }, rootNode)
+    return interceptor.onRenderAndSnapshot(
+      renderProps = currentProps,
+      proceed = { props ->
+        val rendering = rootNode.render(workflow, props)
+        val snapshot = rootNode.snapshot()
+        RenderingAndSnapshot(rendering, snapshot)
+      },
+      session = rootNode.session,
+    )
   }
 
   /**
diff --git a/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/WorkflowNodeTest.kt b/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/StatefulWorkflowNodeTest.kt
similarity index 94%
rename from workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/WorkflowNodeTest.kt
rename to workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/StatefulWorkflowNodeTest.kt
index 5658d59ee0..574e4b9026 100644
--- a/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/WorkflowNodeTest.kt
+++ b/workflow-runtime/src/commonTest/kotlin/com/squareup/workflow1/internal/StatefulWorkflowNodeTest.kt
@@ -55,7 +55,7 @@ import kotlin.test.assertTrue
 import kotlin.test.fail
 
 @Suppress("UNCHECKED_CAST")
-internal class WorkflowNodeTest {
+internal class StatefulWorkflowNodeTest {
 
   abstract class StringWorkflow : StatefulWorkflow<String, String, String, String>() {
     override fun snapshotState(state: String): Snapshot = fail("not expected")
@@ -108,7 +108,7 @@ internal class WorkflowNodeTest {
       oldAndNewProps += old to new
       return@PropsRenderingWorkflow state
     }
-    val node = WorkflowNode(workflow.id(), workflow, "old", null, context)
+    val node = StatefulWorkflowNode(workflow.id(), workflow, "old", null, context)
 
     node.render(workflow, "new")
 
@@ -121,7 +121,7 @@ internal class WorkflowNodeTest {
       oldAndNewProps += old to new
       return@PropsRenderingWorkflow state
     }
-    val node = WorkflowNode(workflow.id(), workflow, "old", null, context)
+    val node = StatefulWorkflowNode(workflow.id(), workflow, "old", null, context)
 
     node.render(workflow, "old")
 
@@ -132,7 +132,7 @@ internal class WorkflowNodeTest {
     val workflow = PropsRenderingWorkflow { old, new, _ ->
       "$old->$new"
     }
-    val node = WorkflowNode(workflow.id(), workflow, "foo", null, context)
+    val node = StatefulWorkflowNode(workflow.id(), workflow, "foo", null, context)
 
     val rendering = node.render(workflow, "foo2")
 
@@ -173,7 +173,7 @@ internal class WorkflowNodeTest {
         return context.eventHandler("") { event -> setOutput(event) }
       }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow,
       "",
@@ -215,7 +215,7 @@ internal class WorkflowNodeTest {
         return context.eventHandler("") { event -> setOutput(event) }
       }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow,
       "",
@@ -267,7 +267,7 @@ internal class WorkflowNodeTest {
         return ""
       }
     }
-    val node = WorkflowNode(workflow.id(), workflow, "", null, context)
+    val node = StatefulWorkflowNode(workflow.id(), workflow, "", null, context)
 
     node.render(workflow, "")
     sink.send(action("") { setOutput("event") })
@@ -284,7 +284,7 @@ internal class WorkflowNodeTest {
       }
       assertFalse(started)
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -305,7 +305,7 @@ internal class WorkflowNodeTest {
         contextFromWorker = coroutineContext
       }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -314,7 +314,10 @@ internal class WorkflowNodeTest {
     )
 
     node.render(workflow.asStatefulWorkflow(), Unit)
-    assertEquals(WorkflowNodeId(workflow).toString(), node.coroutineContext[CoroutineName]!!.name)
+    assertEquals(
+      WorkflowNodeId(workflow).toString(),
+      node.scope.coroutineContext[CoroutineName]!!.name
+    )
     assertEquals(
       "sideEffect[the key] for ${WorkflowNodeId(workflow)}",
       contextFromWorker!![CoroutineName]!!.name
@@ -327,7 +330,7 @@ internal class WorkflowNodeTest {
         actionSink.send(action("") { setOutput("result") })
       }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -359,7 +362,7 @@ internal class WorkflowNodeTest {
         }
       }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = true,
@@ -388,7 +391,7 @@ internal class WorkflowNodeTest {
         }
       }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -417,7 +420,7 @@ internal class WorkflowNodeTest {
         }
       }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = 0,
@@ -445,7 +448,7 @@ internal class WorkflowNodeTest {
         seenProps += props
       }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = 0,
@@ -469,7 +472,7 @@ internal class WorkflowNodeTest {
       runningSideEffect("same") { fail() }
       runningSideEffect("same") { fail() }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -500,7 +503,7 @@ internal class WorkflowNodeTest {
       if (props == 2) runningSideEffect("three", recordingSideEffect(events3))
     }
       .asStatefulWorkflow()
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow,
       initialProps = 0,
@@ -536,7 +539,7 @@ internal class WorkflowNodeTest {
       runningSideEffect("one") { started1 = true }
       runningSideEffect("two") { started2 = true }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -566,7 +569,7 @@ internal class WorkflowNodeTest {
         }
       }
     )
-    val originalNode = WorkflowNode(
+    val originalNode = StatefulWorkflowNode(
       workflow.id(),
       workflow,
       initialProps = "initial props",
@@ -575,10 +578,10 @@ internal class WorkflowNodeTest {
     )
 
     assertEquals("initial props", originalNode.render(workflow, "foo"))
-    val snapshot = originalNode.snapshot(workflow)
+    val snapshot = originalNode.snapshot()
     assertNotEquals(0, snapshot.toByteString().size)
 
-    val restoredNode = WorkflowNode(
+    val restoredNode = StatefulWorkflowNode(
       workflow.id(),
       workflow,
       // These props should be ignored, since snapshot is non-null.
@@ -595,7 +598,7 @@ internal class WorkflowNodeTest {
       render = { _, state -> state },
       snapshot = { Snapshot.of("restored") }
     )
-    val originalNode = WorkflowNode(
+    val originalNode = StatefulWorkflowNode(
       workflow.id(),
       workflow,
       initialProps = "initial props",
@@ -604,10 +607,10 @@ internal class WorkflowNodeTest {
     )
 
     assertEquals("initial props", originalNode.render(workflow, "foo"))
-    val snapshot = originalNode.snapshot(workflow)
+    val snapshot = originalNode.snapshot()
     assertNotEquals(0, snapshot.toByteString().size)
 
-    val restoredNode = WorkflowNode(
+    val restoredNode = StatefulWorkflowNode(
       workflow.id(),
       workflow,
       // These props should be ignored, since snapshot is non-null.
@@ -652,7 +655,7 @@ internal class WorkflowNodeTest {
       }
     )
 
-    val originalNode = WorkflowNode(
+    val originalNode = StatefulWorkflowNode(
       parentWorkflow.id(),
       parentWorkflow,
       initialProps = "initial props",
@@ -661,10 +664,10 @@ internal class WorkflowNodeTest {
     )
 
     assertEquals("initial props|child props", originalNode.render(parentWorkflow, "foo"))
-    val snapshot = originalNode.snapshot(parentWorkflow)
+    val snapshot = originalNode.snapshot()
     assertNotEquals(0, snapshot.toByteString().size)
 
-    val restoredNode = WorkflowNode(
+    val restoredNode = StatefulWorkflowNode(
       parentWorkflow.id(),
       parentWorkflow,
       // These props should be ignored, since snapshot is non-null.
@@ -695,13 +698,13 @@ internal class WorkflowNodeTest {
         }
       }
     )
-    val node = WorkflowNode(workflow.id(), workflow, Unit, null, Unconfined)
+    val node = StatefulWorkflowNode(workflow.id(), workflow, Unit, null, Unconfined)
 
     assertEquals(0, snapshotCalls)
     assertEquals(0, snapshotWrites)
     assertEquals(0, restoreCalls)
 
-    val snapshot = node.snapshot(workflow)
+    val snapshot = node.snapshot()
 
     assertEquals(1, snapshotCalls)
     assertEquals(0, snapshotWrites)
@@ -713,7 +716,7 @@ internal class WorkflowNodeTest {
     assertEquals(1, snapshotWrites)
     assertEquals(0, restoreCalls)
 
-    WorkflowNode(workflow.id(), workflow, Unit, snapshot, Unconfined)
+    StatefulWorkflowNode(workflow.id(), workflow, Unit, snapshot, Unconfined)
 
     assertEquals(1, snapshotCalls)
     assertEquals(1, snapshotWrites)
@@ -732,7 +735,7 @@ internal class WorkflowNodeTest {
       render = { _, state -> state },
       snapshot = { state -> Snapshot.write { it.writeUtf8WithLength(state) } }
     )
-    val originalNode = WorkflowNode(
+    val originalNode = StatefulWorkflowNode(
       workflow.id(),
       workflow,
       initialProps = "initial props",
@@ -741,10 +744,10 @@ internal class WorkflowNodeTest {
     )
 
     assertEquals("initial props", originalNode.render(workflow, "foo"))
-    val snapshot = originalNode.snapshot(workflow)
+    val snapshot = originalNode.snapshot()
     assertNotEquals(0, snapshot.toByteString().size)
 
-    val restoredNode = WorkflowNode(
+    val restoredNode = StatefulWorkflowNode(
       workflow.id(),
       workflow,
       initialProps = "new props",
@@ -756,7 +759,7 @@ internal class WorkflowNodeTest {
 
   @Test fun toString_formats_as_WorkflowInstance_without_parent() {
     val workflow = Workflow.rendering<Nothing, Unit>(Unit)
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       id = workflow.id(key = "foo"),
       workflow = workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -774,7 +777,7 @@ internal class WorkflowNodeTest {
 
   @Test fun toString_formats_as_WorkflowInstance_with_parent() {
     val workflow = Workflow.rendering<Nothing, Unit>(Unit)
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       id = workflow.id(key = "foo"),
       workflow = workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -807,7 +810,7 @@ internal class WorkflowNodeTest {
       }
     }
     val workflow = Workflow.rendering<Nothing, Unit>(Unit)
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       id = workflow.id(key = "foo"),
       workflow = workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -817,7 +820,7 @@ internal class WorkflowNodeTest {
       parent = TestSession(42)
     )
 
-    assertSame(node.coroutineContext, interceptedScope.coroutineContext)
+    assertSame(node.scope.coroutineContext, interceptedScope.coroutineContext)
     assertEquals(workflow.identifier, interceptedSession.identifier)
     assertEquals(0, interceptedSession.sessionId)
     assertEquals("foo", interceptedSession.renderKey)
@@ -848,7 +851,7 @@ internal class WorkflowNodeTest {
       }
     }
     val workflow = Workflow.rendering<Nothing, Unit>(Unit)
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       id = workflow.id(key = "foo"),
       workflow = workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -859,7 +862,7 @@ internal class WorkflowNodeTest {
       parent = TestSession(42)
     )
 
-    assertSame(node.coroutineContext, interceptedScope.coroutineContext)
+    assertSame(node.scope.coroutineContext, interceptedScope.coroutineContext)
     assertEquals(workflow.identifier, interceptedSession.identifier)
     assertEquals(0, interceptedSession.sessionId)
     assertEquals("foo", interceptedSession.renderKey)
@@ -895,7 +898,7 @@ internal class WorkflowNodeTest {
       initialState = { props -> "state($props)" },
       render = { _, _ -> fail() }
     )
-    WorkflowNode(
+    StatefulWorkflowNode(
       id = workflow.id(key = "foo"),
       workflow = workflow.asStatefulWorkflow(),
       initialProps = "props",
@@ -941,7 +944,7 @@ internal class WorkflowNodeTest {
       onPropsChanged = { old, new, state -> "onPropsChanged($old, $new, $state)" },
       render = { _, state -> state }
     )
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       id = workflow.id(key = "foo"),
       workflow = workflow.asStatefulWorkflow(),
       initialProps = "old",
@@ -987,7 +990,7 @@ internal class WorkflowNodeTest {
       initialState = { "state" },
       render = { props, state -> "render($props, $state)" }
     )
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       id = workflow.id(key = "foo"),
       workflow = workflow.asStatefulWorkflow(),
       initialProps = "props",
@@ -1029,7 +1032,7 @@ internal class WorkflowNodeTest {
       render = { _, state -> state },
       snapshot = { state -> Snapshot.of("snapshot($state)") }
     )
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       id = workflow.id(key = "foo"),
       workflow = workflow.asStatefulWorkflow(),
       initialProps = "old",
@@ -1038,7 +1041,7 @@ internal class WorkflowNodeTest {
       baseContext = Unconfined,
       parent = TestSession(42)
     )
-    val snapshot = node.snapshot(workflow)
+    val snapshot = node.snapshot()
 
     assertEquals("state", interceptedState)
     assertEquals(Snapshot.of("snapshot(state)"), interceptedSnapshot)
@@ -1070,7 +1073,7 @@ internal class WorkflowNodeTest {
       render = { _, state -> state },
       snapshot = { null }
     )
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       id = workflow.id(key = "foo"),
       workflow = workflow.asStatefulWorkflow(),
       initialProps = "old",
@@ -1079,7 +1082,7 @@ internal class WorkflowNodeTest {
       baseContext = Unconfined,
       parent = TestSession(42)
     )
-    val snapshot = node.snapshot(workflow)
+    val snapshot = node.snapshot()
 
     assertEquals("state", interceptedState)
     assertNull(interceptedSnapshot)
@@ -1111,7 +1114,7 @@ internal class WorkflowNodeTest {
         "root(${renderChild(leafWorkflow, props)})"
       }
     )
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       id = rootWorkflow.id(key = "foo"),
       workflow = rootWorkflow.asStatefulWorkflow(),
       initialProps = "props",
@@ -1131,7 +1134,7 @@ internal class WorkflowNodeTest {
       val sink = eventHandler("eventHandler") { fail("Expected handler to fail.") }
       sink()
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -1159,7 +1162,7 @@ internal class WorkflowNodeTest {
     val workflow = Workflow.stateless {
       actionSink.send(TestAction())
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -1186,7 +1189,7 @@ internal class WorkflowNodeTest {
         }
       }
     )
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -1211,7 +1214,7 @@ internal class WorkflowNodeTest {
     val workflow = Workflow.stateless<Unit, String, Sink<String>> {
       actionSink.contraMap { action("") { setOutput(it) } }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -1238,7 +1241,7 @@ internal class WorkflowNodeTest {
     val workflow = Workflow.stateless<Unit, String?, Sink<String?>> {
       actionSink.contraMap { action("") { setOutput(null) } }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -1269,7 +1272,7 @@ internal class WorkflowNodeTest {
         return@stateful renderState
       }
     )
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -1292,7 +1295,7 @@ internal class WorkflowNodeTest {
         actionSink.send(action("") { setOutput("child:hello") })
       }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -1318,7 +1321,7 @@ internal class WorkflowNodeTest {
         actionSink.send(action("") { setOutput(null) })
       }
     }
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       workflow.asStatefulWorkflow(),
       initialProps = Unit,
@@ -1343,7 +1346,7 @@ internal class WorkflowNodeTest {
     }
     val stateful = workflow.asStatefulWorkflow()
 
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       stateful,
       initialProps = "",
@@ -1367,7 +1370,7 @@ internal class WorkflowNodeTest {
       remember(key, typeOf<String>(), input) { value }
     }
     val stateful = workflow.asStatefulWorkflow()
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       stateful,
       initialProps = "",
@@ -1393,7 +1396,7 @@ internal class WorkflowNodeTest {
       remember(key, returnType) { value }
     }
     val stateful = workflow.asStatefulWorkflow()
-    val node = WorkflowNode(
+    val node = StatefulWorkflowNode(
       workflow.id(),
       stateful,
       initialProps = "" to ("" as Any),

From 05cad4438217a2cc6a0b7aabb7bccafe01a25205 Mon Sep 17 00:00:00 2001
From: Zach Klippenstein <git@zachklipp.com>
Date: Mon, 14 Jul 2025 16:48:15 -0700
Subject: [PATCH 2/2] Rename AbstractWorkflowNode to WorkflowNode.

This intermediate rename was to help git show the correct history for StatefulWorkflowNode.
---
 .../squareup/workflow1/internal/StatefulWorkflowNode.kt   | 2 +-
 .../com/squareup/workflow1/internal/SubtreeManager.kt     | 4 ++--
 .../com/squareup/workflow1/internal/WorkflowChildNode.kt  | 8 ++++----
 .../internal/{AbstractWorkflowNode.kt => WorkflowNode.kt} | 4 ++--
 4 files changed, 9 insertions(+), 9 deletions(-)
 rename workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/{AbstractWorkflowNode.kt => WorkflowNode.kt} (97%)

diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/StatefulWorkflowNode.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/StatefulWorkflowNode.kt
index b8f195b54b..aa09861d09 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/StatefulWorkflowNode.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/StatefulWorkflowNode.kt
@@ -62,7 +62,7 @@ internal class StatefulWorkflowNode<PropsT, StateT, OutputT, RenderingT>(
   override val parent: WorkflowSession? = null,
   interceptor: WorkflowInterceptor = NoopWorkflowInterceptor,
   idCounter: IdCounter? = null
-) : AbstractWorkflowNode<PropsT, OutputT, RenderingT>(
+) : WorkflowNode<PropsT, OutputT, RenderingT>(
   id = id,
   baseContext = baseContext,
   interceptor = interceptor,
diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/SubtreeManager.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/SubtreeManager.kt
index 62c0010ea9..60d79ccf51 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/SubtreeManager.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/SubtreeManager.kt
@@ -20,7 +20,7 @@ import kotlin.coroutines.CoroutineContext
  * Responsible for tracking child workflows, starting them and tearing them down when necessary.
  * Also manages restoring children from snapshots.
  *
- * Child workflows are stored in [WorkflowChildNode]s, which associate the child's [AbstractWorkflowNode]
+ * Child workflows are stored in [WorkflowChildNode]s, which associate the child's [WorkflowNode]
  * with its output handler.
  *
  * ## Rendering
@@ -147,7 +147,7 @@ internal class SubtreeManager<PropsT, StateT, OutputT>(
   }
 
   /**
-   * Uses [selector] to invoke [AbstractWorkflowNode.registerTreeActionSelectors] for every running child
+   * Uses [selector] to invoke [WorkflowNode.registerTreeActionSelectors] for every running child
    * workflow this instance is managing.
    */
   fun registerChildActionSelectors(selector: SelectBuilder<ActionProcessingResult>) {
diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowChildNode.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowChildNode.kt
index 329174c5bd..87648454d4 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowChildNode.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowChildNode.kt
@@ -9,7 +9,7 @@ import com.squareup.workflow1.trace
 /**
  * Representation of a child workflow that has been rendered by another workflow.
  *
- * Associates the child's [AbstractWorkflowNode] (which includes the key passed to `renderChild`) with the
+ * Associates the child's [WorkflowNode] (which includes the key passed to `renderChild`) with the
  * output handler function that was passed to `renderChild`.
  */
 internal class WorkflowChildNode<
@@ -21,11 +21,11 @@ internal class WorkflowChildNode<
   >(
   val workflow: Workflow<*, ChildOutputT, *>,
   private var handler: (ChildOutputT) -> WorkflowAction<ParentPropsT, ParentStateT, ParentOutputT>,
-  val workflowNode: AbstractWorkflowNode<ChildPropsT, ChildOutputT, *>
+  val workflowNode: WorkflowNode<ChildPropsT, ChildOutputT, *>
 ) : InlineListNode<WorkflowChildNode<*, *, *, *, *>> {
   override var nextListNode: WorkflowChildNode<*, *, *, *, *>? = null
 
-  /** The [AbstractWorkflowNode]'s [WorkflowNodeId]. */
+  /** The [WorkflowNode]'s [WorkflowNodeId]. */
   val id get() = workflowNode.id
 
   /**
@@ -47,7 +47,7 @@ internal class WorkflowChildNode<
   }
 
   /**
-   * Wrapper around [AbstractWorkflowNode.render] that allows calling it with erased types.
+   * Wrapper around [WorkflowNode.render] that allows calling it with erased types.
    */
   fun <R> render(
     workflow: Workflow<*, *, *>,
diff --git a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/AbstractWorkflowNode.kt b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowNode.kt
similarity index 97%
rename from workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/AbstractWorkflowNode.kt
rename to workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowNode.kt
index 18df86a7c0..1253492875 100644
--- a/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/AbstractWorkflowNode.kt
+++ b/workflow-runtime/src/commonMain/kotlin/com/squareup/workflow1/internal/WorkflowNode.kt
@@ -32,7 +32,7 @@ internal fun <PropsT, OutputT, RenderingT> createWorkflowNode(
   parent: WorkflowSession? = null,
   interceptor: WorkflowInterceptor = NoopWorkflowInterceptor,
   idCounter: IdCounter? = null
-): AbstractWorkflowNode<PropsT, OutputT, RenderingT> = StatefulWorkflowNode(
+): WorkflowNode<PropsT, OutputT, RenderingT> = StatefulWorkflowNode(
   id = id,
   workflow = workflow.asStatefulWorkflow(),
   initialProps = initialProps,
@@ -46,7 +46,7 @@ internal fun <PropsT, OutputT, RenderingT> createWorkflowNode(
   idCounter = idCounter,
 )
 
-internal abstract class AbstractWorkflowNode<PropsT, OutputT, RenderingT>(
+internal abstract class WorkflowNode<PropsT, OutputT, RenderingT>(
   val id: WorkflowNodeId,
   protected val interceptor: WorkflowInterceptor,
   protected val emitAppliedActionToParent: (ActionApplied<OutputT>) -> ActionProcessingResult,